Christopher J. VandenBussche

Multicentre validation of a microRNA-based assay for diagnosing indeterminate thyroid nodules utilising fine needle aspirate smears

Aims The distinction between benign and malignant thyroid nodules has important therapeutic implications. Our objective was to develop an assay that could classify indeterminate thyroid nodules as benign or suspicious, using routinely prepared fine needle aspirate (FNA) cytology smears. Methods A training set of 375 FNA smears was used to develop the microRNA-based assay, which was validated using a blinded, multicentre, retrospective cohort of 201 smears. Final diagnosis of the validation samples was determined based on corresponding surgical specimens, reviewed by the contributing institute pathologist and two independent pathologists. Validation samples were from adult patients (≥18u2005years) with nodule size >0.5u2005cm, and a final diagnosis confirmed by at least one of the two blinded, independent pathologists. The developed assay, RosettaGX Reveal, differentiates benign from malignant thyroid nodules, using quantitative RT-PCR. Results Test performance on the 189 samples that passed quality control: negative predictive value: 91% (95% CI 84% to 96%); sensitivity: 85% (CI 74% to 93%); specificity: 72% (CI 63% to 79%). Performance for cases in which all three reviewing pathologists were in agreement regarding the final diagnosis (n=150): negative predictive value: 99% (CI 94% to 100%); sensitivity: 98% (CI 87% to 100%); specificity: 78% (CI 69% to 85%). Conclusions A novel assay utilising microRNA expression in cytology smears was developed. The assay distinguishes benign from malignant thyroid nodules using a single FNA stained smear, and does not require fresh tissue or special collection and shipment conditions. This assay offers a valuable tool for the preoperative classification of thyroid samples with indeterminate cytology.

Adequacy in voided urine cytology specimens: The role of volume and a repeat void upon predictive values for high‐grade urothelial carcinoma

Adequacy assessment is one of the most controversial and overlooked components in the daily practice of cytopathology, because it is generally determined from limited samples. Because voided urine varies widely in terms of its volume and cellularity, there is little consensus about the proper role for these variables in assessing specimen adequacy. In this study, the authors explored the role of volume in voided urine specimens to determine whether it plays a role in determining adequacy for the detection of high‐grade urothelial carcinoma.

Improved risk stratification for patients with high-grade urothelial carcinoma following application of the Paris System for Reporting Urinary Cytology

The Paris System for Reporting Urinary Cytology (TPS) requires 4 cytomorphologic criteria for a definitive diagnosis of high‐grade urothelial carcinoma (HGUC) in urinary tract cytology (UTC) specimens: an elevated nuclear‐to‐cytoplasmic (N/C) ratio (at or above 0.7), markedly atypical nuclear borders, moderate to severe hyperchromasia, and coarse chromatin. However, malignant UTC specimens often contain degenerative changes, and this limits the number of malignant cells meeting all 4 TPS cytomorphologic criteria.

Analytical validity of a microRNA-based assay for diagnosing indeterminate thyroid FNA smears from routinely prepared cytology slides

The majority of thyroid nodules are diagnosed using fine‐needle aspiration (FNA) biopsies. The authors recently described the clinical validation of a molecular microRNA‐based assay, RosettaGX Reveal, which can diagnose thyroid nodules as benign or suspicious using a single stained FNA smear. This paper describes the analytical validation of the assay.

Should the BK polyomavirus cytopathic effect be best classified as atypical or benign in urine cytology specimens

According to The Paris System for Reporting Urinary Cytology (TPS), the category of atypical urothelial cells (AUC) should not be applied to specimens in which cellular changes can be entirely attributed to the polyoma (BK) virus cytopathic effect (CPE). Until recently, cases with BK CPE at The Johns Hopkins Hospital were categorized as atypical urothelial cells of uncertain significance (AUC‐US), which is equivalent to the TPS AUC category. This study was performed to determine how significantly the rate of AUC‐US specimens would decrease if specimens with only BK CPE were classified as benign.

The cytomorphological features of low-grade urothelial neoplasms vary by specimen type

Urinary tract (UT) cytology has been used successfully to diagnose high‐grade urothelial carcinoma but is reported to have poor sensitivity for low‐grade urothelial neoplasms (LGUNs). However, the literature has shown that LGUN may be associated with atypical findings in UT specimens. The authors determined which features were most commonly observed, and whether the method of specimen procurement had an effect.

Morphologists overestimate the nuclear-to-cytoplasmic ratio.

The Paris System for Reporting Urinary Cytology (TPS) has defined nuclear‐to‐cytoplasmic (N:C) ratio cutoff values for several of its risk‐stratified diagnostic categories. However, because pathologists are not trained to recognize strict N:C ratio cutoff values, a previously designed survey was used to determine whether pathologists could accurately identify N:C ratios according to TPS standards.

YAP1 and COX2 coordinately regulate urothelial cancer stem-like cells

Overcoming acquired drug resistance remains a core challenge in the clinical management of human cancer, including in urothelial carcinoma of the bladder (UCB). Cancer stem-like cells (CSC) have been implicated in the emergence of drug resistance but mechanisms and intervention points are not completely understood. Here, we report that the proinflammatory COX2/PGE2 pathway and the YAP1 growth-regulatory pathway cooperate to recruit the stem cell factor SOX2 in expanding and sustaining the accumulation of urothelial CSCs. Mechanistically, COX2/PGE2 signaling induced promoter methylation of let-7, resulting in its downregulation and subsequent SOX2 upregulation. YAP1 induced SOX2 expression more directly by binding its enhancer region. In UCB clinical specimens, positive correlations in the expression of SOX2, COX2, and YAP1 were observed, with coexpression of COX2 and YAP1 particularly commonly observed. Additional investigations suggested that activation of the COX2/PGE2 and YAP1 pathways also promoted acquired resistance to EGFR inhibitors in basal-type UCB. In a mouse xenograft model of UCB, dual inhibition of COX2 and YAP1 elicited a long-lasting therapeutic response by limiting CSC expansion after chemotherapy and EGFR inhibition. Our findings provide a preclinical rationale to target these pathways concurrently with systemic chemotherapy as a strategy to improve the clinical management of UCB.Significance: These findings offer a preclinical rationale to target the COX2 and YAP1 pathways concurrently with systemic chemotherapy to improve the clinical management of UCB, based on evidence that these two pathways expand cancer stem-like cell populations that mediate resistance to chemotherapy. Cancer Res; 78(1); 168-81. ©2017 AACR.

Alternative lengthening of telomeres and ATRX/DAXX loss can be reliably detected in FNAs of pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) frequently use the alternative lengthening of telomeres (ALT) pathway for telomere maintenance. ALT is strongly correlated with α thalassemia‐mental retardation, X linked (ATRX), and death domain‐associated protein 6 (DAXX) alterations and a poor prognosis in patients with primary PanNET. Because fine‐needle aspiration (FNA) is a noninvasive way to sample tumors, the authors evaluated whether they could accurately detect ALT and loss of ATRX/DAXX in a primary PanNET cohort of FNAs.

When words matter: A "suspicious" urinary tract cytology diagnosis improves patient follow-up among nonurologists

Urinary tract cytology (UTC) specimens diagnosed using high‐risk indeterminate categories such as “atypical urothelial cells, cannot exclude high‐grade urothelial carcinoma” (AUC‐H) or “suspicious for high‐grade urothelial carcinoma” (SHGUC) have a high rate of detection of high‐grade urothelial carcinoma on subsequent biopsy. Although urologists are familiar with such terminology, it is unclear whether patients receive appropriate follow‐up when UTC is ordered by nonurologists. In the current study, the authors investigated whether the use of AUC‐H versus SHGUC altered patient management among nonurologists.